The basic form of roof lighting system comprises a substantially horizontal glazed input aperture in the roof, a substantially horizontal output aperture in the ceiling of the room below and a passageway with reflective interior walls that connects the two apertures. Natural light passing through the system provides natural illumination to the room below. This basic form of roof lighting system is ineffective in accepting and transmitting low elevation sunlight to the room below. The reasons for poor transmission of low elevation sunlight are: (a) The projected area of input aperture reduces as sin(E) where E is the sun elevation. (b) Low elevation sunlight suffers high reflection loss at the glazed input aperture. (c) Low elevation sunlight suffers many reflections within the reflective passageway and loses energy at each reflection. Thus natural illumination via roof lights tends to be poor in the early morning and late afternoon and in winter when the sun is at low elevation angle. Conversely, this basic form accepts and transmits high elevation light very effectively. However this may lead to overheating of the room below during the middle of the day in summer when the sun is at high elevation angle. It is therefore desirable to have a means of increasing the acceptance and transmittance of a roof lighting system when the sun elevation angle is low and a means of decreasing the acceptance and transmittance when the sun elevation is high. It is possible to use optical means for light redirection to alter the angular dependence of the acceptance and transmission of a roof lighting system. A roof light with optical means for light redirection is said to be angle-selective.